.. include:: replace.txt
.. highlight:: cpp

.. _sec-wifi-changelog-doc:

++++++++++++++++++++++++++++++++++++++++
API and behavior changes across releases
++++++++++++++++++++++++++++++++++++++++

This page tracks the most relevant changes to the API and behavior of the wifi
module occurred across the various releases of |ns3|.

ChannelSettings attribute
+++++++++++++++++++++++++

Prior to ns-3.36, channels, channel widths, and operating bands were set
separately.  As of ns-3.36, a new tuple object that we call ChannelSettings has
consolidated all of these settings.  Users should specify the channel number,
channel width, frequency band, and primary channel index as a tuple (and
continue to set the Wi-Fi standard separately). Since ns-3.43, this attribute
can contain multiple tuples to support 80+80MHz operating channels.

For instance, where pre-ns-3.36 code may have said::

    WifiPhyHelper phy;
    phy.Set("ChannelNumber", UintegerValue(36));

the equivalent new code is::

    WifiPhyHelper phy;
    phy.Set("ChannelSettings", StringValue("{36, 20, BAND_5GHZ, 0}"));

which denotes that channel 36 is used on a 20 MHz channel in the 5GHz band,
and because a larger channel width greater than 20 MHz is not being used, there
is no need to indicate the primary 20 MHz channel so it is set to zero in the
last argument. Users can read :ref:`Channel-settings` for more details.
